add os[1-8]-ref for os refereces, add guide, add README

os2-ref/.cargo/config

@@ -0,0 +1,7 @@
+[build]
+target = "riscv64gc-unknown-none-elf"
+
+[target.riscv64gc-unknown-none-elf]
+rustflags = [
+    "-Clink-arg=-Tsrc/linker.ld", "-Cforce-frame-pointers=yes"
+]

os2-ref/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+name = "os"
+version = "0.1.0"
+authors = ["Yifan Wu <shinbokuow@163.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+lazy_static = { version = "1.4.0", features = ["spin_no_std"] }
+log = "0.4"
+riscv = { git = "https://gitee.com/rcore-os/riscv", features = ["inline-asm"] }

os2-ref/Makefile

@@ -0,0 +1,58 @@
+# Building
+TARGET := riscv64gc-unknown-none-elf
+MODE := release
+KERNEL_ELF := target/$(TARGET)/$(MODE)/os
+KERNEL_BIN := $(KERNEL_ELF).bin
+KERNEL_ASM := $(KERNEL_ELF).asm
+
+# BOARD
+BOARD ?= qemu
+SBI ?= rustsbi
+BOOTLOADER := ../bootloader/$(SBI)-$(BOARD).bin
+
+# KERNEL ENTRY
+KERNEL_ENTRY_PA := 0x80200000
+
+# Binutils
+OBJDUMP := rust-objdump --arch-name=riscv64
+OBJCOPY := rust-objcopy --binary-architecture=riscv64
+
+CHAPTER ?= $(shell git rev-parse --abbrev-ref HEAD | grep -oP 'ch\K[0-9]')
+TEST ?= $(CHAPTER)
+BASE ?= 1
+
+build: env $(KERNEL_BIN)
+
+$(KERNEL_BIN): kernel
+	@$(OBJCOPY) $(KERNEL_ELF) --strip-all -O binary $@
+
+disasm:
+	@$(OBJDUMP) $(KERNEL_ELF) -S > $(KERNEL_ELF).asm
+
+env:
+	(rustup target list | grep "riscv64gc-unknown-none-elf (installed)") || rustup target add $(TARGET)
+	cargo install cargo-binutils --vers ~0.3
+	rustup component add rust-src
+	rustup component add llvm-tools-preview
+
+kernel:
+	@make -C ../user build TEST=$(TEST) CHAPTER=$(CHAPTER) BASE=$(BASE)
+	@cargo build --release
+
+clean:
+	@cargo clean
+
+run: build
+	@qemu-system-riscv64 \
+		-machine virt \
+		-nographic \
+		-bios $(BOOTLOADER) \
+		-device loader,file=$(KERNEL_BIN),addr=$(KERNEL_ENTRY_PA)
+
+debug: build
+	@tmux new-session -d \
+		"qemu-system-riscv64 -machine virt -nographic -bios $(BOOTLOADER) -device loader,file=$(KERNEL_BIN),addr=$(KERNEL_ENTRY_PA) -s -S" && \
+		tmux split-window -h "riscv64-unknown-elf-gdb -ex 'file $(KERNEL_ELF)' -ex 'set arch riscv:rv64' -ex 'target remote localhost:1234'" && \
+		tmux -2 attach-session -d
+
+.PHONY: build env kernel clean run-inner

os2-ref/build.rs

@@ -0,0 +1,56 @@
+use std::fs::{read_dir, File};
+use std::io::{Result, Write};
+
+fn main() {
+    println!("cargo:rerun-if-changed=../user/src/");
+    println!("cargo:rerun-if-changed={}", TARGET_PATH);
+    insert_app_data().unwrap();
+}
+
+static TARGET_PATH: &str = "../user/build/bin/";
+
+fn insert_app_data() -> Result<()> {
+    let mut f = File::create("src/link_app.S").unwrap();
+    let mut apps: Vec<_> = read_dir("../user/build/bin/")
+        .unwrap()
+        .into_iter()
+        .map(|dir_entry| {
+            let mut name_with_ext = dir_entry.unwrap().file_name().into_string().unwrap();
+            name_with_ext.drain(name_with_ext.find('.').unwrap()..name_with_ext.len());
+            name_with_ext
+        })
+        .collect();
+    apps.sort();
+
+    writeln!(
+        f,
+        r#"
+    .align 3
+    .section .data
+    .global _num_app
+_num_app:
+    .quad {}"#,
+        apps.len()
+    )?;
+
+    for i in 0..apps.len() {
+        writeln!(f, r#"    .quad app_{}_start"#, i)?;
+    }
+    writeln!(f, r#"    .quad app_{}_end"#, apps.len() - 1)?;
+
+    for (idx, app) in apps.iter().enumerate() {
+        println!("app_{}: {}", idx, app);
+        writeln!(
+            f,
+            r#"
+    .section .data
+    .global app_{0}_start
+    .global app_{0}_end
+app_{0}_start:
+    .incbin "{2}{1}.bin"
+app_{0}_end:"#,
+            idx, app, TARGET_PATH
+        )?;
+    }
+    Ok(())
+}

os2-ref/src/batch.rs

@@ -0,0 +1,141 @@
+use crate::sync::UPSafeCell;
+use crate::trap::TrapContext;
+use lazy_static::*;
+
+const USER_STACK_SIZE: usize = 4096;
+const KERNEL_STACK_SIZE: usize = 4096 * 2;
+const MAX_APP_NUM: usize = 16;
+const APP_BASE_ADDRESS: usize = 0x80400000;
+const APP_SIZE_LIMIT: usize = 0x20000;
+
+#[repr(align(4096))]
+struct KernelStack {
+    data: [u8; KERNEL_STACK_SIZE],
+}
+
+#[repr(align(4096))]
+struct UserStack {
+    data: [u8; USER_STACK_SIZE],
+}
+
+static KERNEL_STACK: KernelStack = KernelStack {
+    data: [0; KERNEL_STACK_SIZE],
+};
+static USER_STACK: UserStack = UserStack {
+    data: [0; USER_STACK_SIZE],
+};
+
+impl KernelStack {
+    fn get_sp(&self) -> usize {
+        self.data.as_ptr() as usize + KERNEL_STACK_SIZE
+    }
+    pub fn push_context(&self, cx: TrapContext) -> &'static mut TrapContext {
+        let cx_ptr = (self.get_sp() - core::mem::size_of::<TrapContext>()) as *mut TrapContext;
+        unsafe {
+            *cx_ptr = cx;
+        }
+        unsafe { cx_ptr.as_mut().unwrap() }
+    }
+}
+
+impl UserStack {
+    fn get_sp(&self) -> usize {
+        self.data.as_ptr() as usize + USER_STACK_SIZE
+    }
+}
+
+struct AppManager {
+    num_app: usize,
+    current_app: usize,
+    app_start: [usize; MAX_APP_NUM + 1],
+}
+
+impl AppManager {
+    pub fn print_app_info(&self) {
+        info!("[kernel] num_app = {}", self.num_app);
+        for i in 0..self.num_app {
+            info!(
+                "[kernel] app_{} [{:#x}, {:#x})",
+                i,
+                self.app_start[i],
+                self.app_start[i + 1]
+            );
+        }
+    }
+
+    unsafe fn load_app(&self, app_id: usize) {
+        if app_id >= self.num_app {
+            panic!("All applications completed!");
+        }
+        info!("[kernel] Loading app_{}", app_id);
+        // clear icache
+        core::arch::asm!("fence.i");
+        // clear app area
+        core::slice::from_raw_parts_mut(APP_BASE_ADDRESS as *mut u8, APP_SIZE_LIMIT).fill(0);
+        let app_src = core::slice::from_raw_parts(
+            self.app_start[app_id] as *const u8,
+            self.app_start[app_id + 1] - self.app_start[app_id],
+        );
+        let app_dst = core::slice::from_raw_parts_mut(APP_BASE_ADDRESS as *mut u8, app_src.len());
+        app_dst.copy_from_slice(app_src);
+    }
+
+    pub fn get_current_app(&self) -> usize {
+        self.current_app
+    }
+
+    pub fn move_to_next_app(&mut self) {
+        self.current_app += 1;
+    }
+}
+
+lazy_static! {
+    static ref APP_MANAGER: UPSafeCell<AppManager> = unsafe {
+        UPSafeCell::new({
+            extern "C" {
+                fn _num_app();
+            }
+            let num_app_ptr = _num_app as usize as *const usize;
+            let num_app = num_app_ptr.read_volatile();
+            let mut app_start: [usize; MAX_APP_NUM + 1] = [0; MAX_APP_NUM + 1];
+            let app_start_raw: &[usize] =
+                core::slice::from_raw_parts(num_app_ptr.add(1), num_app + 1);
+            app_start[..=num_app].copy_from_slice(app_start_raw);
+            AppManager {
+                num_app,
+                current_app: 0,
+                app_start,
+            }
+        })
+    };
+}
+
+pub fn init() {
+    print_app_info();
+}
+
+pub fn print_app_info() {
+    APP_MANAGER.exclusive_access().print_app_info();
+}
+
+pub fn run_next_app() -> ! {
+    let mut app_manager = APP_MANAGER.exclusive_access();
+    let current_app = app_manager.get_current_app();
+    unsafe {
+        app_manager.load_app(current_app);
+    }
+    app_manager.move_to_next_app();
+    drop(app_manager);
+    // before this we have to drop local variables related to resources manually
+    // and release the resources
+    extern "C" {
+        fn __restore(cx_addr: usize);
+    }
+    unsafe {
+        __restore(KERNEL_STACK.push_context(TrapContext::app_init_context(
+            APP_BASE_ADDRESS,
+            USER_STACK.get_sp(),
+        )) as *const _ as usize);
+    }
+    panic!("Unreachable in batch::run_current_app!");
+}

os2-ref/src/console.rs

@@ -0,0 +1,37 @@
+/*！
+
+本模块实现了 print 和 println 宏。
+
+*/
+
+use crate::sbi::console_putchar;
+use core::fmt::{self, Write};
+
+struct Stdout;
+
+impl Write for Stdout {
+    fn write_str(&mut self, s: &str) -> fmt::Result {
+        for c in s.chars() {
+            console_putchar(c as usize);
+        }
+        Ok(())
+    }
+}
+
+pub fn print(args: fmt::Arguments) {
+    Stdout.write_fmt(args).unwrap();
+}
+
+#[macro_export]
+macro_rules! print {
+    ($fmt: literal $(, $($arg: tt)+)?) => {
+        $crate::console::print(format_args!($fmt $(, $($arg)+)?));
+    }
+}
+
+#[macro_export]
+macro_rules! println {
+    ($fmt: literal $(, $($arg: tt)+)?) => {
+        $crate::console::print(format_args!(concat!($fmt, "\n") $(, $($arg)+)?));
+    }
+}

os2-ref/src/entry.asm

@@ -0,0 +1,12 @@
+    .section .text.entry
+    .globl _start
+_start:
+    la sp, boot_stack_top
+    call rust_main
+
+    .section .bss.stack
+    .globl boot_stack
+boot_stack:
+    .space 4096 * 16
+    .globl boot_stack_top
+boot_stack_top:

os2-ref/src/lang_items.rs

@@ -0,0 +1,17 @@
+use crate::sbi::shutdown;
+use core::panic::PanicInfo;
+
+#[panic_handler]
+fn panic(info: &PanicInfo) -> ! {
+    if let Some(location) = info.location() {
+        println!(
+            "Panicked at {}:{} {}",
+            location.file(),
+            location.line(),
+            info.message().unwrap()
+        );
+    } else {
+        println!("Panicked: {}", info.message().unwrap());
+    }
+    shutdown()
+}

os2-ref/src/linker.ld

@@ -0,0 +1,48 @@
+OUTPUT_ARCH(riscv)
+ENTRY(_start)
+BASE_ADDRESS = 0x80200000;
+
+SECTIONS
+{
+    . = BASE_ADDRESS;
+    skernel = .;
+
+    stext = .;
+    .text : {
+        *(.text.entry)
+        *(.text .text.*)
+    }
+
+    . = ALIGN(4K);
+    etext = .;
+    srodata = .;
+    .rodata : {
+        *(.rodata .rodata.*)
+        *(.srodata .srodata.*)
+    }
+
+    . = ALIGN(4K);
+    erodata = .;
+    sdata = .;
+    .data : {
+        *(.data .data.*)
+        *(.sdata .sdata.*)
+    }
+
+    . = ALIGN(4K);
+    edata = .;
+    .bss : {
+        *(.bss.stack)
+        sbss = .;
+        *(.bss .bss.*)
+        *(.sbss .sbss.*)
+    }
+
+    . = ALIGN(4K);
+    ebss = .;
+    ekernel = .;
+
+    /DISCARD/ : {
+        *(.eh_frame)
+    }
+}

os2-ref/src/logging.rs

@@ -0,0 +1,47 @@
+/*！
+
+本模块利用 log crate 为你提供了日志功能，使用方式见 main.rs.
+
+*/
+
+use log::{self, Level, LevelFilter, Log, Metadata, Record};
+
+struct SimpleLogger;
+
+impl Log for SimpleLogger {
+    fn enabled(&self, _metadata: &Metadata) -> bool {
+        true
+    }
+    fn log(&self, record: &Record) {
+        if !self.enabled(record.metadata()) {
+            return;
+        }
+        let color = match record.level() {
+            Level::Error => 31, // Red
+            Level::Warn => 93,  // BrightYellow
+            Level::Info => 34,  // Blue
+            Level::Debug => 32, // Green
+            Level::Trace => 90, // BrightBlack
+        };
+        println!(
+            "\u{1B}[{}m[{:>5}] {}\u{1B}[0m",
+            color,
+            record.level(),
+            record.args(),
+        );
+    }
+    fn flush(&self) {}
+}
+
+pub fn init() {
+    static LOGGER: SimpleLogger = SimpleLogger;
+    log::set_logger(&LOGGER).unwrap();
+    log::set_max_level(match option_env!("LOG") {
+        Some("ERROR") => LevelFilter::Error,
+        Some("WARN") => LevelFilter::Warn,
+        Some("INFO") => LevelFilter::Info,
+        Some("DEBUG") => LevelFilter::Debug,
+        Some("TRACE") => LevelFilter::Trace,
+        _ => LevelFilter::Off,
+    });
+}

os2-ref/src/main.rs

@@ -0,0 +1,40 @@
+#![no_std]
+#![no_main]
+#![feature(panic_info_message)]
+
+#[macro_use]
+extern crate log;
+
+#[macro_use]
+mod console;
+mod batch;
+mod lang_items;
+mod logging;
+mod sbi;
+mod sync;
+mod syscall;
+mod trap;
+
+core::arch::global_asm!(include_str!("entry.asm"));
+core::arch::global_asm!(include_str!("link_app.S"));
+
+fn clear_bss() {
+    extern "C" {
+        fn sbss();
+        fn ebss();
+    }
+    unsafe {
+        core::slice::from_raw_parts_mut(sbss as usize as *mut u8, ebss as usize - sbss as usize)
+            .fill(0);
+    }
+}
+
+#[no_mangle]
+pub fn rust_main() -> ! {
+    clear_bss();
+    logging::init();
+    println!("[kernel] Hello, world!");
+    trap::init();
+    batch::init();
+    batch::run_next_app();
+}

os2-ref/src/sbi.rs

@@ -0,0 +1,34 @@
+#![allow(unused)]
+
+const SBI_SET_TIMER: usize = 0;
+const SBI_CONSOLE_PUTCHAR: usize = 1;
+const SBI_CONSOLE_GETCHAR: usize = 2;
+const SBI_SHUTDOWN: usize = 8;
+
+#[inline(always)]
+fn sbi_call(which: usize, arg0: usize, arg1: usize, arg2: usize) -> usize {
+    let mut ret;
+    unsafe {
+        core::arch::asm!(
+            "ecall",
+            inlateout("x10") arg0 => ret,
+            in("x11") arg1,
+            in("x12") arg2,
+            in("x17") which,
+        );
+    }
+    ret
+}
+
+pub fn console_putchar(c: usize) {
+    sbi_call(SBI_CONSOLE_PUTCHAR, c, 0, 0);
+}
+
+pub fn console_getchar() -> usize {
+    sbi_call(SBI_CONSOLE_GETCHAR, 0, 0, 0)
+}
+
+pub fn shutdown() -> ! {
+    sbi_call(SBI_SHUTDOWN, 0, 0, 0);
+    panic!("It should shutdown!");
+}

os2-ref/src/sync/mod.rs

@@ -0,0 +1,3 @@
+mod up;
+
+pub use up::UPSafeCell;

os2-ref/src/sync/up.rs

@@ -0,0 +1,29 @@
+use core::cell::{RefCell, RefMut};
+
+/// Wrap a static data structure inside it so that we are
+/// able to access it without any `unsafe`.
+///
+/// We should only use it in uniprocessor.
+///
+/// In order to get mutable reference of inner data, call
+/// `exclusive_access`.
+pub struct UPSafeCell<T> {
+    /// inner data
+    inner: RefCell<T>,
+}
+
+unsafe impl<T> Sync for UPSafeCell<T> {}
+
+impl<T> UPSafeCell<T> {
+    /// User is responsible to guarantee that inner struct is only used in
+    /// uniprocessor.
+    pub unsafe fn new(value: T) -> Self {
+        Self {
+            inner: RefCell::new(value),
+        }
+    }
+    /// Panic if the data has been borrowed.
+    pub fn exclusive_access(&self) -> RefMut<'_, T> {
+        self.inner.borrow_mut()
+    }
+}

os2-ref/src/syscall/fs.rs

@@ -0,0 +1,15 @@
+const FD_STDOUT: usize = 1;
+
+pub fn sys_write(fd: usize, buf: *const u8, len: usize) -> isize {
+    match fd {
+        FD_STDOUT => {
+            let slice = unsafe { core::slice::from_raw_parts(buf, len) };
+            let str = core::str::from_utf8(slice).unwrap();
+            print!("{}", str);
+            len as isize
+        }
+        _ => {
+            panic!("Unsupported fd in sys_write!");
+        }
+    }
+}

os2-ref/src/syscall/mod.rs

@@ -0,0 +1,16 @@
+const SYSCALL_WRITE: usize = 64;
+const SYSCALL_EXIT: usize = 93;
+
+mod fs;
+mod process;
+
+use fs::*;
+use process::*;
+
+pub fn syscall(syscall_id: usize, args: [usize; 3]) -> isize {
+    match syscall_id {
+        SYSCALL_WRITE => sys_write(args[0], args[1] as *const u8, args[2]),
+        SYSCALL_EXIT => sys_exit(args[0] as i32),
+        _ => panic!("Unsupported syscall_id: {}", syscall_id),
+    }
+}

os2-ref/src/syscall/process.rs

@@ -0,0 +1,6 @@
+use crate::batch::run_next_app;
+
+pub fn sys_exit(exit_code: i32) -> ! {
+    info!("[kernel] Application exited with code {}", exit_code);
+    run_next_app()
+}

os2-ref/src/trap/context.rs

@@ -0,0 +1,25 @@
+use riscv::register::sstatus::{self, Sstatus, SPP};
+
+#[repr(C)]
+pub struct TrapContext {
+    pub x: [usize; 32],
+    pub sstatus: Sstatus,
+    pub sepc: usize,
+}
+
+impl TrapContext {
+    pub fn set_sp(&mut self, sp: usize) {
+        self.x[2] = sp;
+    }
+    pub fn app_init_context(entry: usize, sp: usize) -> Self {
+        let mut sstatus = sstatus::read();
+        sstatus.set_spp(SPP::User);
+        let mut cx = Self {
+            x: [0; 32],
+            sstatus,
+            sepc: entry,
+        };
+        cx.set_sp(sp);
+        cx
+    }
+}

os2-ref/src/trap/mod.rs

@@ -0,0 +1,50 @@
+mod context;
+
+use crate::batch::run_next_app;
+use crate::syscall::syscall;
+use riscv::register::{
+    mtvec::TrapMode,
+    scause::{self, Exception, Trap},
+    stval, stvec,
+};
+
+core::arch::global_asm!(include_str!("trap.S"));
+
+pub fn init() {
+    extern "C" {
+        fn __alltraps();
+    }
+    unsafe {
+        stvec::write(__alltraps as usize, TrapMode::Direct);
+    }
+}
+
+#[no_mangle]
+pub fn trap_handler(cx: &mut TrapContext) -> &mut TrapContext {
+    let scause = scause::read();
+    let stval = stval::read();
+    match scause.cause() {
+        Trap::Exception(Exception::UserEnvCall) => {
+            cx.sepc += 4;
+            cx.x[10] = syscall(cx.x[17], [cx.x[10], cx.x[11], cx.x[12]]) as usize;
+        }
+        Trap::Exception(Exception::StoreFault) | Trap::Exception(Exception::StorePageFault) => {
+            error!("[kernel] PageFault in application, core dumped.");
+            run_next_app();
+        }
+        Trap::Exception(Exception::IllegalInstruction) => {
+            error!("[kernel] IllegalInstruction in application, core dumped.");
+            run_next_app();
+        }
+        _ => {
+            panic!(
+                "Unsupported trap {:?}, stval = {:#x}!",
+                scause.cause(),
+                stval
+            );
+        }
+    }
+    cx
+}
+
+pub use context::TrapContext;

os2-ref/src/trap/trap.S

@@ -0,0 +1,64 @@
+.altmacro
+.macro SAVE_GP n
+    sd x\n, \n*8(sp)
+.endm
+.macro LOAD_GP n
+    ld x\n, \n*8(sp)
+.endm
+    .section .text
+    .globl __alltraps
+    .globl __restore
+    .align 2
+__alltraps:
+    csrrw sp, sscratch, sp
+    # now sp->kernel stack, sscratch->user stack
+    # allocate a TrapContext on kernel stack
+    addi sp, sp, -34*8
+    # save general-purpose registers
+    sd x1, 1*8(sp)
+    # skip sp(x2), we will save it later
+    sd x3, 3*8(sp)
+    # skip tp(x4), application does not use it
+    # save x5~x31
+    .set n, 5
+    .rept 27
+        SAVE_GP %n
+        .set n, n+1
+    .endr
+    # we can use t0/t1/t2 freely, because they were saved on kernel stack
+    csrr t0, sstatus
+    csrr t1, sepc
+    sd t0, 32*8(sp)
+    sd t1, 33*8(sp)
+    # read user stack from sscratch and save it on the kernel stack
+    csrr t2, sscratch
+    sd t2, 2*8(sp)
+    # set input argument of trap_handler(cx: &mut TrapContext)
+    mv a0, sp
+    call trap_handler
+
+__restore:
+    # case1: start running app by __restore
+    # case2: back to U after handling trap
+    mv sp, a0
+    # now sp->kernel stack(after allocated), sscratch->user stack
+    # restore sstatus/sepc
+    ld t0, 32*8(sp)
+    ld t1, 33*8(sp)
+    ld t2, 2*8(sp)
+    csrw sstatus, t0
+    csrw sepc, t1
+    csrw sscratch, t2
+    # restore general-purpuse registers except sp/tp
+    ld x1, 1*8(sp)
+    ld x3, 3*8(sp)
+    .set n, 5
+    .rept 27
+        LOAD_GP %n
+        .set n, n+1
+    .endr
+    # release TrapContext on kernel stack
+    addi sp, sp, 34*8
+    # now sp->kernel stack, sscratch->user stack
+    csrrw sp, sscratch, sp
+    sret